Casio was established in April 1946 by Tadao Kashio (樫尾忠雄), an engineer specializing in fabrication technology. Kashio's first major product was the yubiwa pipe, a finger ring that would hold a cigarette, allowing the wearer to smoke the cigarette down to its nub while also leaving the wearer's hands free. Japan was impoverished immediately following World War II, so cigarettes were valuable, and the invention was a success.
After seeing the electric calculators at the first Business Show in Ginza, Tokyo in 1949, Kashio and his younger brothers used their profits from the yubiwa pipe to develop their own calculators. Most of the calculators at that time worked using gears and could be operated by hand using a crank or using a motor (see adding machine). Kashio possessed some knowledge of electronics, and set out to make a calculator using solenoids. The desk-sized calculator was finished in 1954 and was Japan's first electro-mechanical calculator. One of the central innovations of the calculator was its adoption of the 10-key number pad; at that time other calculators were using a "full keypad", which meant that each place in the number (1s, 10s, 100s, etc...) had nine keys. Another innovation was the use of a single display window instead of the three display windows (one for each argument and one for the answer) used in other calculators.
Casio's products include calculators, watches, cash registers, illuminators, digital cameras (Exilim Series), film cameras, laptop and sub-notebook computers, mobile phones, electronic keyboards, PDAs (E-Data Bank), electronic dictionaries, Digital Diaries, electronic games, computer printers, clocks, and portable televisions.